Method of electroplating cylinders



METHOD OF ELECTROPLATING CYLINDERS Filed Dec. :23, 194s SSheets-Sheet 1 SOLUTION LEVEL COPPER 7 STR/PP/NG o/sLsc-rklcf FLTER Z0 M it 7 SUPPORT/N6 PLATE ABLE 5 E INVENTOR. S/LA 5 CO OLSON in] A5 BY ATTORNEY Feb. 10, 1948. v s. COULSON 2,435,872

METHOD OF ELIECTROPLATING CYLINDERS Filed Dec. 25, 1943 Sheets-Sheet 2 INVENTOR.

BY S/LAS ,cou so/v '20 g g ATToRA EX Feb. 10,1948. S N I 2,435,872

I S/LAS COULSON ATTORNEY Patented Feb. 10, 1948 UNITED STATES-PATENT OFFICE METHOD OF ELECTROPLATING CYLINDERS Silas Coulson, Jaclrson Heights, N. Y.

Application December 23, 1943, Serial No. 515,441

This invention relates to the electroplating of rotogravure printing cylinders and is directed more particularly to the provision of a method the present invention may be conveniently sup-- whereby thin copper shells taken from rotogravure cylinders, that have been etched and that have served their purpose, may be employed as anode copper for the plating of the same or another cylinder. Heretofore it has been the practice to dispose of the used shells and to employ solid bars of copper made expressly for the purpose by melting down such shells into such bars and by using virgin copper for this purpose. Because of the present war effort, however, it is becoming increasingly difficult to obtain these copper bars, and the object of the present invention is to provide a method whereby used shells may be employed as a substitute therefor.

I'am aware that copper scrap has heretofore been employed in the electroplating field, but the use of such scrap has never been satisfactory in the plating of rotogravure cylinders. Such scrap has generally been deposited within foraminous baskets and similar receptacles in such manner that the distance between various portions of the scrap andthe surface of the cyl-. inder varies to such degree thatno satisfactory deposition of the plate upon the cylinder was possible. Experience has shown that, in order to obtain satisfactory plating of a substantially uniform shell upon the cylinder, it is necessary to maintain a substantially uniform distance between the anode and thecathode, particularly where a heavy electric current flow is maintained between these parts and where scrap is deposited in a basket or. simlar container such a condition cannot possibly, persist during the period necessary to eifectually plate a rotogravure cylinder.

In practically carrying out the present invention, a cylinder which has servedits purpose, is divestedof its embracing copper shell by slitting the shell longitudinally and stripping the same from the cylinder. The shell'may be then either slit longitudinally into strips of convenient' width or it may be folded transversely to appropriate size and flattened between rollers or manually as may be desired. The resulting flattened shell is thereupon associated with one or more frames which are'of arcuate form and so disposed that their axes are common to the axis of the cylinder to be plated. The frames are immersed in an electrolyte and the copper shell associated therewith thereupon becomes the anode of the electroplating apparatus. l

The frame or frames employed in carrying out 9 Claims. (Cl. 204-25) ported in proper cooperative relation to the cathode cylinder by a cradle of the character disclosed in the Ernest S. Ballard Patent No. 1,918,627, issued .July 18, 1933, or the Emil Ericksson Patent No. 2,055,070, issued September 22, 1936. In both cases the electrolyte is contained within a tank providedwith bearings for supporting a rotogravure cylinder for rotation, with. an appreciable portion of the circumference of such cylinder immersed in the electrolyte. Mounted within the'tank is a cradle which underlies the submerged portion of the cylinder andhas a curvature coaxial with said cylinder. The cradle serves to substantially isolate a portion' of the electrolyte between it and the surface of the cylinder, so that, as the cylinder is rotated, a substantially uniform flow of electrolyte passes through the space thus provided, thereby giving a substantially uniform ionic discharge between the cradle which serves as the anode and the cylinder which functions as the cathode.

In the Ballard patent the anode copper is supplied directly from the electrolyte solution, while in the Ericksson patent the copper is supplied from solid copper anode bars, such as I have hereinbefore referred to. By the present invention, the copper bars of the Ericksson patent may be wholly or partially replaced by stripped copper shell, the same being held in proper spaced cooperative relative to the surface of the cylinder by the frame or frames of this invention, as will be presently'explained.

The most eflicient spacing of the copper shell is accomplished by the mounting of the frame or frames in a cradle and this spacing of the frame or frames may be adjusted with respect to the cylinder bymeans of lead spacers interposed between the frame and the supporting surface of the cradle.

An important feature of the present invention resides in the fact'that all parts of the anode copper are at substantially uniform distances from the cathode, in contradistinction to the use of deepanode scrap baskets of prior practice. By employingthis close uniform spacing, wherein all parts of the anode copper substantially parallel the surface of the cylinder, I am able tuting and employing my anode frames, that they are held by gravity in proper cooperative relation with the cathode cylinder. As the distance between these parts is small and the copper anode shells are relatively thin, I interpose between said shells and the cathode a filter of any appropriate material which will not be detrimentally affected by the electrolyte, such, for example, as glass fibre cloth or wool. fe1t.. This filter not only serves to filter the electrolyte; but will hold down the copper shell, which has a tendency to curl or bulge as it becomes thin during use. The use of a filter in this connection, op-

erating as specified, constitutes a. feature of this invention.

The filter is, according to this invention, preferably placed between the frame andthe anode copper and may, if desired, be permanently secured to the frame, so that the filter is held down and serves, in turn, to hold down and properly space the copper shell from thecathode.

Features of: the invention, other than 2 those adverted to, will be apparentfromxthe hereinafterdetailed description andiclaims, when read in conjunction with the accompanying drawings.

The accompanyingv drawingsillustrate difierent practical structures.- for carrying out the method of the invention, but the constructions thereinshownare tobe: understood as il1ustrative, only, and not as: defining the limitsof. the invention.

Figure 1 is an endfielevation of a rotogravure cylinder partiallycsubmerged :in an electrolyte solution and positioned in cooperative relation with a subjacent cradle on which issupporte-d a pair of cooperating frames embodying thepresent invention.

Figure 2 is a fragmental section on the line 2'-2 of Figure 1.

Figure 3 is a perspective view of 'one of the frames shown in Figures 1 and 2.:

Figure 4 is a plan view of an alternate: form of frame.

Figure 5- is an edge elevation; viewed 'from' the lower edge asseen in Figure 4.

Figure 6 is:a view similar to Fig. 1, but showing a modified form of the invention with the" frame thereof. illustrated in: transverse-sections.

Figure 7 isa planview of the frame of Figure 6 removedxfrom the 1 remainder of thesapparatus.

Figure 8 is a plan view ofaa further modified form 0f frame;

Figure 9 is a cross section of apreviously-plated cylinder, provided with a-used shelhwhich' is adapted to be. stripped :tobe employed: as'a source of: anode copper; this figure showingthe: shell as cut, preliminary to the stripping.v

Figures 10-17, inclusive,-show successive steps inthe manipulation of one or morevsuch shells tocondition them to be'used as a source'of anode copper according to this invention;

Inthe accompanying drawings, .i' designates the electrolyte level in anappropriate electroplating tank (not shown) in'iwhich issupported a oradle 2 of arcuatecross section. A rotogravure printing cylinder '3 is-shown as rotatably supported in any 'suitable manner partiallyv immer'sed in the electrolyte; coaxial with the cradle 25 and in spacedrelation thereto; Positiveelectrical current is fed'to'the" cradle 2, whichcis generally of. lead, while the negative pole-ofthe circuit is connected' to the cylinder 3: which, in practice, has apolishe'd surface adapted toreceive the copper deposit in the form of auni-form plated coating -about its periphery.

In the form of the invention shown in Figures 1-3 inclusive, there is laid within the cradle a plurality of arcuate bar spacers 4 of which any suitable number may be used, conveniently three or four. These arcuate spacers are preferably of lead or of some other suitable conductive material. On the spacers is positioned a conductive supporting plate 5 extending for the full length of the cylinderv 3 and preferably of lead. The copper shells which have been stripped from used cylinders and flattened or cut into strips, as the case may be, are adapted to be laid upon the supporting plate 5 which constitutes a supporting floor therefor and in such manner as to rest upon and conform to the shape of said plate. Pivoted to the opposite ends of the spacers 4- or plate 5- are frames 6, one of which is shown in Figure 3. Each such frame comprises end arms-6w having a curvature with the same center as the curvature of the cylinder and the cradle and extending between these arms are rods 1 rigidly secured thereto 1 and cooperating therewith. to collectively form the frame. All of the frame parts are dielectric. They may be made of any suitable material such as steel covered by lead or rubber but they should be rendered di'-' electric in any appropriate way, as by adielectric coating.

Oneend of each of the arms 6a is perforated, as shown at 8, and onthe correspondingends of the spacers 4 orplate 5 are upstanding lugs similarly perforated. Between the perforated ends ofthe arms 6a of each of the frames ex tends a bar it which istpreferably of the same thickness as the radial thickness ofthe arms 6a. Thisbar t may have a hole through: its center registering, with the" perforations 8 in. the arms of the frame and rods 9 extendthrough thedo'ar, the lugsof the spacers and through the per forations Bof'the armsv andthus mount each of the frames for pivotal movement. The-barst of thetwo frames are important since they'estab'-" lishuniform throats-T between the pivoted sides ofthe-frames and the surface of the'cylinder, for reasonshereinafter more fully explained;

The-flattened copper shells H are placed: in the cradle before the cylinder'3 to be electroplated is brought'into cooperative relation and thus it is possible toswing-the freev ends of the frames. upwardly and outwardly as indicatedi-in dotted lines inFigure 1, so 'as' to" uncover the supportingplate 5; The copper shellsxare then laid upon-said plate and over these shells-is placed a thinmattress-or filter l0 ofxfibre' glass, wool felt, orthe like; so as to completely. cover the copper shells, and thereafter the lead frames 6"are swunginto the full line positions of- Figure 1. As shown in Figure 2,-the rods 1 are of such length that the armsta liebeyond the ends" of the supporting plate 5' and thus the "weight of the frames is transmitted through the rods 1 directly on to .the filter lfl' which, in turn, bears upon and holds the several-thicknesses of the copper shells ll together and to a firm seaton the. supportingplate 5. Any appropriate number of copper shells or parts of shells ,may be held. down inthis manner-and the Weight of the frames is sufiicient to hold themv in close conformity with the supportingplate as the-electrolyzing operation proceeds. The filter) is of course pervious to electronic action and d'oes'not interfere with the passage; of copper" therethrough, to be deposited upon the cylinder 3-, as the latter revolves in the usual -way .tovpresent different portions of its peripheral face to the action of electrolysis,

It is important, moreover, to note that, as the cylinderrotates in the direction of the arrow in Figure 1, there 'is a constant circulation of the electrolyte between the filter and the cylinder. The intake supply of this, flow is in the form of a throat T which is unchanging in its dimension and consequently the flow is constant. Furthermore, since the rods 1 extend transversely of the flow, they cause considerable agitation or turbulence therein, and thus facilitate the electrolytic action. The surface of the anode copper shells is so great that their combined thickness need not be appreciable. Thus, even as they are electrolytically worn away, the distance between the anode copper and the cylinder will not increase to such extent as to interfere with a substantially uniform electrolytic deposition 'of the copper.

As the electrolytic operation proceeds, the couper anode shells will of course become very thin andfragile and, in the absence of the filter, would tend to curl up and might, if the intervening space between the anode and cathode were small, contact with the latter and short circuit theshell. With the filter present this cannot occur. However, as the copper shells are used up, the weight of the pivoted frames causes them to continue to bear firmlydown upon the anode copper and hold it to a firm seat against the supporting plate 5.

'After the cylinder 3 has been plated to the desired extent in the manner specified, said cylinder is removed, the frames swung outwardly and additionally stripped and flattened copper shells are introduced into the cradle in the manner hereinbefore specified, in order that the next cylinder may be plated in the same way.

In Figures 4 and 5, I have shown a modified form of frame. Herea rectangular framework [2, which may conveniently be of lead and is of arcuate form to correspond to the shape of the arms Ed, is strung with wires l3similar to the manner of stringing a tennis racket, except that none of the wires 13 should be normal to the longitudinal sides of the framework l2. By preference the wires may conveniently extend at 60 and 30, respectively, or 75 and 15, respectively, or'at other appropriate angles, so that none of the wires will extendin the directionof flow of the electrolyte current through the throat T, nor will wire intersections line up in the direction of such flow. With this. arrangement, said intersections will be staggered transversely of the direction of the electrolyte flow to such extent as to produce maximum turbulence of the electrolyte as it passes over the frame because the intersections will agitate the electrolyte and, since no two are in line, such agitation will be broadcast throughout the entire surface of the frame.

Where wires are strung in the manner described, they are preferably secured to one another at their points of crossing to render the structure more firm and rigid. In practice, I may, in lieu of the wire construction shown, employ an interwoven wire construction or openwork or reticulated metal plates may be secured on the framework I 2. In any event, wires or metal plates used in this connection should be either of a di-electric material or properly rendered di-electric with appropriate coatings or otherwise. The filter l4, used .in connection with the frame of these figures, may be loosely laid on the anode copper, as inFigures land 2,01 said filter may be clamped to the framework l2, as shown in Figure 5; by'means of cleats 15, held in place by screws 6,'which thread into the framework, as here shown.: yIt is also possible and in some instances desirable to also clamp the lateral edges of the anode'copper shells to the framework by the cleats I5, so that the entire assembly of the frame, filter and anode copper shells can be efsuch an arrangement, however, the structure of Figures 4. and 5 should be so used that, when placed in the cradle, it is positioned below frames 6 so that the rods 1 of these frames will serve to hold down the filter and keep it free from contact with the cylinder.

The frame of Figures 4, and 5 is shown ofthe same size as one of the frames in Figure 1 and twoof these frames may be laid in the cradle on the supporting plate 5,-so as to loosely rest on said plate by gravity. However, the frame of Figure 4 maybe made wide enough so that one frame, instead of two, may be used to cover the width of the supporting plate 5. Furthermore,-elther one orboth of these frames, as the case may be, may be pivotally secured to the supporting plate or spacers as described with respect to Figure 1, to be pivotally movable in the same manner as one of the frames in Figure 1. The frame of Figures 4 and 5 may be made of material which may be buoyant in the elec- 'trolyte' in which case the frame may be weighted down in-any suitable manner as by using copper bars, as hereinafter described in connection with the structure ,of Figures 6 and 7.

For the purpose of illustration, I have shown theframe in these latter figures as made of wood. It has arcuate end bars [1, while its side bars [8 are approximately one-half thethickness of the end bars n, so that cleats l9, corresponding to the cleats [5, may serve to clamp between them and the side bars "[8, the filter Malone or to gether with one or more :copper anode shells.

Rods 19, corresponding to the rods I, extend longitudinally of the frame and through perforations in the end bars I! thereof and these rods are held in place by external cleats 20 permanently secured to the outer faces of the end bars 11.

The frame shown in Figure 7 may be used with spacers 4 and a supporting plate 5, as described with respect to the previous figures, but in Fig ure 6 it is shown as supported within the cradle on lead bars 2|. Between the bars 2| are positioned lead bars 22 which are sufiiciently thicker than the lead bars 2| to reach into the confines of'the frame and form' a direct support for the copper anode shells. The leadbars 2| and 2i! are not affected by the electrolytic action and their thickness thus remains constant so that the throat T in this figure will also remain constant.

The frame of Figure 6 may be held to its seat on the bars 2| by weights 23 which may be of lead, but said weights are shown as bars of copper to augment the supply of copper inherent in the copper shells. The thickness of the bars 2| and'22 will of course depend upon the diameter of the cylinder 3 which is to be plated and the same of course holds true-of the thicknesszof. the spacers 4 in Figure 2.

I have hereinbefore. referred to. certain: parts as made off-lead; The reason: for-employing lead is math is not seriously affected bythexelectrm lyte nor does it pollute the same. I .am..aware, however, that other materials which-are resistant in the same way, or which may be coated-by resistant materials, maybe employed .in. lieu of lead, provided that they have the requisite di-. electric or conductive properties. For example I may use Monel. metal, stainless'steel, hard rubher; or plastic materials, either' aloneorincom-bi nation with one another, asthe casesmaybe, in the form of bars, rods, strip's,zor in the shape of angle iron or channelciron to-build: upthe parts which I have described. Where partslare made or a-metal which is a. conductor of electricity, it may be necessary to coatthev same with an -insulating substance to preventthe S123 ions from; breaking into S02 ions .plus oxygen and which gases would be lost throughithe solution, whereasthe S04 ions. should combine with the copper of the anode to form CuSOr. and thusaugmerit the electrolyte-solution:

It will be apparent from theforegoingdescription that, when employing. the present invention, the distance between the anode and cathode is practically uniform or so close to uniform asto not materially vary the'electrolytic deposition of the copper upon the cylinder. In fact. the variation in distance between the anode. and cathode of this-invention, duetov dissolving of:the anode as the electrolytic action proceeds, is materially less perceptible than under that prion-practice wherein copper bars are employed as a source of anode copper for these copper bars, which initially may be one inch or more. in: thickness, are commonly used until they are dissolved away to a small fractionof that dimension; As-the bars dissolve the distance. between the anodeand the cathode becomes correspondingly great. Such an increase in this distance cannot possibly occur with thep'resent invention:

The flow of the solutionflthrough the throat and'the interveningv space: between the frame and the cylinder is. uniform and such. beingthe'case, the operator is assuredrof rapid depositof that fine. crystalline: structure so desirable; of vrotogravure cylinders. Particular attention: is directed to the fact that the: thin copperanode shells-are properly supported throughout their; entire extentsand. this in itself makesiit possible topreserve that uniform distanceof. ionicflow' so necess sary to uniform plating.

Furthermore, the rodsof .the frameoriwires, as the. case may be,- operate as. baflles. to: produce additional agitation .inthe electrolyte flow: as to keep'th'e. cathode: filrrriricl'i incopper. ions-and the anode film rich insulphateions, thereby as-- suring true. and uniform shells and alsoeven-conrosion f the anode.

The filter cloth .willreffectua'lly prevent. any-ink or t foreign substance which .has been left onthe anode copper shells. from reaching; the-:cylinder and at the same time, it.will.prevent suchcurling of the-thin shells. as mightresultin short acirrcuiting vofsthe apparatus...

In: the prior use of. copper barst'assa-source of anode copper, the surfaces; of such barsv are uniformly flat, so thattheyv presentra'substantially uniform exposed surface to. the action of the electrolyte. This is not the: case. when astripped printing. shellris employed as invthe presenttinyention. In fact, the surface of; such shell is microscopically undulating or uneven due. to the etching which has previously been performed on the surface thereof. Moreover, thisxetchingis ncttordinarily uniform throughout thezsurface of the shell.v One portion. of the surfacev may be wholly unetched; Consequently the ionic flow over the etched. portion: of the shell willbefrom a. considerably greatersurface area than-from the wretched. portionof. the shell. with consequent ununiiormity' in .the copper ion; feed. If, e. g., one. endof ashell. is: etched and the other end wholly unetched, a much'riche'r flow oicopper wouldvresult .from the. etched .end,. with resulting tendency to produce an uneven deposition of cop per upon the cylinder.

I have provided definite means for overcoming such a. condition. In Figure 8, Ihaveshown a frame. (on asomewhat smallerscale than in the preceding figures) adapted to compensate. for the uneven character of an etched shell: This frame. is shown. as comprising a framework 24 with arcuateends and with longitudinal intermediate-stay bars 25and acrossith'e frameare a series of rods 26.which correspond, according to certain of their functions,.to the-rods I and the wires 1.! 3.. It: will be noted, however, that these rods26 are of: serpentineform, so that the portions 12! of .therods are inclined in one. direction with respect: tothe electrolyte flow;through the throats T, whilethe portions 28 of said .rods are inclined in the opposite direction. Asaresult of this construction, the electrolyte, flowing through the intake throat T, will meet with the portions 21, 28,21 in successionand these. in."- clined: portions will serve. as baffles'to causethe elecrolytev flow'to be. deflected first toward one end oithe cylinder andthen toward the other endxof the cylinder. Inotherwordsas the electrolyte flowsbetween the anode and the cathode, it is swept in. one direction. longitudinally of'the cylinder and then inJthe opposite longitudinal direction and this. longitudinal; sweeping: of the flow alternately in opposite directions will effecta lateral agitation which. will distribute the more heavily copper: charged .solution uniformly through'the space between the anode and'the cathode and thus render the deposition onthe latter uniform.

It will also benoted'in Figure 8 that the intersections of the rods 26 with the sidebars of the frame and withthe-stay bars 25 are staggered in the direction of flow of the electrolyte to .obtairrz maximumturbulence as .hereinbefore described. I realize oficoursethatthe rods 26 may be. of other shapes than as shown, but a generally herringbone pattern" will give satisfactory results. The. longitudinalsideqbars of'the' frame in the structure of Figure" 8 forms the throats T to: which reference has hereinbefore' been made.

In the different figures .ofthe drawings, I:have shown frames of various forms; certain ,of which have bars for holding down the filter and the copperv anode shells .andanother of which is in the form-of a framework with wires extending across the. same. Both the rod andcwire form of frames constitutes grids and. these constructions, as well as equivalent forms, will be generally referred to as such in the appendedclaims;

The method of this invention thus comprises, generallyspeaking, thestripping of electrolyticale lydeposited or plated shells from cylinders-the flattening of these shellsand then the holding of them in coaxially spaced relation to arotating. cylinder. while. submerged in .an electrolyte, with "concurrent. passage or, electricity: between the shells and the cylinder to be plated,- so that the shells will serve as a source'of the anode copper.

. As hereinbefore stated, the shells to be thus used may, after removal fromthe cylinder, be either flattened or cut into strips. According to the preferred form of the invention, the shells are manipulated in a particular way and fora specific purpose which will next be explained.

I have found that if the shells are merely bent into overlapping relation or cut into strips, as stated, the lateral edges of the flattened shells or strips dissolve more rapidly under the action of, the electrolyte and the ionic flow.

The present invention includes a novel method of manipulating the copper shells before they are placed on the support beneath the grid, so that these shells will have reinforcedthickened lateral edges, providing in these locations morecopper than throughout the other portions of the expanse of the shells to compensate for the increased copper draw therefrom and to further provide marginal reinforcements. Thisrein-' forcement of the lateral edges of the anode copper maybe accomplished'in various ways. However, I have'illustrated in Figs; 9-17' one way in which this may be accomplished;

r After a previously plated cylinder has served its purposes; the shell is removed therefrom by forming one longitudinal'slit at one point in the circumference of the cylinder. In Fig. 9, such a cylinder is indicated by the reference character 30, while the used shell is indicated at 3|; In this figureandin the succeeding figures, the shellis shownin the form of a heavy line to indicate its thickness as these shells are quite thin and cross sectioning of such a thin shell is not feasible. Furthermore, in Figs. 11-17, where the shell is shown as bent, as hereinafter described, the bends are illustrated as slightly open, so as to more clearly show the character of the operation, but it will be understood that where bends are indicated the opposing parts will be manipulated into substantially face abutting relation.

To remove the shell3l from the cylinder 30 in Fig. 1, a single cut 32, as. by a razor blade or some other sharp implement, is provided longitudinally of the cylinder and in a directionparallel to its axis. Thereafter the shell is stripped from the cylinder and flattened as shown in Fig. 10. The opposite end portions of the shell are folded upon themselves, as shown in Fig, 11, and thereafter either or both ends of the shell may be again returned upon itself, as indicated in Fig. 12, wherein the left hand end is shown as thus manipulated. One or more folds may be made as desired. This folding of the edge portions, marginally along the opposite lateral edges of the shell, form thickened reinforced edges. After the edges have been reinforced as stated, one lateral half of the shell is thereupon folded on to the other lateral half to form two opposed leaves 33and 34, as indicated in Fig. 13. 7

Two or more shells, manipulated in the manner described, may be then interfoliated as shown, e. g., 'in Figs. 14, 15 and 16, so as to provide a sufiicient quantity of the anode copper desired and, after they have been thus interfltted, they are next manipulated into the flattened arcuate form shown in Fig. 1'7, to have a curvature corresponding to the supporting plate of Fig. 2, or other support which is to mount them in proper cooperativ relation with the cylinder 3 of Fig. 1. Manipulation of the shells into this arcuate form may be accomplished either before, during or after the positioning 0. the shells on such sup-' porting plate 5, or other support, and the grid and filter may be concurrently or subsequently placed overthe assembled shells, so that they may thereafter be used as a source of anode copper, in carrying out the method hereinbefore described.

When the shells ar folded as stated, the re-' sulting anode copper will have thickened reinforced lateral edges which will, as it is dissipated under the ionic flow, provide at such lateral edges a sufiicient excess of copper to hold these edges intact as the electroplating operation proceeds. Experience has shown that by thus reinforcing the edges of the anode copper more efficient re sults are obtained. More rapid plating is possible by following my procedure which will provide more copper at the edges of the thin anode.

The foregoing detailed description sets forth the invention in its preferred practical form, but the invention is to be understood as fully commensurate with the appended claims. Copper has been referred to as the plating metal but other substitute metals, whose use may be required under Wartime emergency, are within the in-' vention,

This'application is a continuation-in-part of my application, Serial No. 423,750, filed December 20, 1941, which matured into Patent No. 2.351,; 586, dated June 20, 1944. My said former application contains claims to practical forms of apparatus for carrying out the method of the present application.

Having thus fully described the invention, what I claim as new. and desire to secure by Letters Patent is:

1. In the art of electroplating cylinders, wherein electric current is passed through an electrolyte from a soluble-anode across an intervening space to the continguous surface of a cathode cylinder to be plated, the method which comprises: physically stripping a plated shell from a previously plated cylinder, thereafter physically manipulating the stripped shell into flattened arcuate form and restraining it in such flattened arcuate form in the electrolyte in a position wherein it is in substantially coaxial spaced relation to the cylinder to be plated while feeding the positive electric current to such shell to cause it to serve as the anode. -2. In the art of electroplating cylinders, wherein electric current is passed through an electrolyte from a soluble anode across an intervening space to the contiguous surface of a cathode cylinder to be plated, the method which comprises: physically stripping a plated shell from a previously plated cylinder, thereafter folding the stripped shell substantially medially of its width to bring the lateral halves thereof into substantially face abutting relation with said halves collectively in flattened form, and shaping said folded shell into flattened arcuate form and restraining it in such flattened arcuate form in the electrolyte in substantially coaxial spaced relation to the cylinder to be plated while feeding the positive electric current to such shell to cause it to serve as the anode.

3. In the art of electroplating cylinders, wherein electric current is passed through an electrolyte from an anode across an intervening space to the contiguous surface of a cathode cylinder to be plated, the method which comprises: physically stripping an electrolytically deposited shell from a previously plated cylinder, folding back the lateral margins of said shell respectively upon themselves -to provide reinforced lateral edges, then folding the shell transversely to bring the successive transverse portions thereof into substantially face abutting relation with-said portions collectively in flatteneol arcuate form, and holding the thus' flattened shell in substantially coaxial spaced relation to the cylinder to be plated while feeding the positive-electric current on the: shell to cause it to serve 'as the anode.

4."-In the art of electroplating cylinderswherein electric current is passed through anelectrolyte from ananode across .an intervening space to the contiguous surface of: a cathode cylinder "to beplate'd,"the method which comprises: physically stripping an "electrolytically deposited shell from a previously plated cylinder, folding back the-lateral margins of-said shellzrespectively upon themselves to provide'reinforced lateral edges, thenfolding the shell :substahtiallytmedially of its width 1 to bring :the 'lateral halves thereof into substantially face :abutting relation with. :said lateral halves collectively in -flattened Jarcuate form, tar-1d :holdin'g the thus fiattenedishelliin substantially coaxial spaced -relation iito the cylinder to be'plated while :feeding 1the rpositive electric current on the shell to cause it torserve as the anode.

:5. In ltheiart of'ilectroplating: cylindersywherein electric currentcisrpassed'through an .:electrolyte from ananode across aninterveningspace to the contiguous ssurface of a :cathode cylinder to be: plated, ,the method which:.comprises: .physically stripping a plurality cf.electrolyticallytdeposited shells from .a corresponding number. ;of previously plated cylinders, :tfolding each :shell transversely to bring successive transverse'ipon tions thereof into substantially .face. abutting relation, interfoliating. said shells; physically manipulating said shells into ifiattened .arcuate form, and holding the thus assembled manipulated shells in substantially ccoaXial spaced relation .ztO th-e:cylinder. to be plated while feeding the:posi-- tive electric current .to the shells to cause .them to collectively-serve as the anode.

6. In the artiof' electroplating cylinders'wherein 'electric'current ispassed through an .electrolyterfrom an anode across an intervening space to the contiguous surfaceofacathodecylinder to be plated, the methodwhich comprises: physically stripping a plurality of electrolytically .deposited shells from .acorresponding number-of previously plated cylinders, :folding rback the lateral margins of each .shell respectively upon themselves to provide reinforced lateral edges on each-shell, then =.folding eeach shell. substantially mediallyof its-width to :bring .the lateral halves thereof into substantially :face .abutting relation, interfoliating said shells, physically manipulating .said shells .into flattened .arcuate form, and holding the :thus' assembled :manipulated :shells in .substantially coaxial spaced :relation to the cylinder 'to be plated while feeding the positive electriccurrent to the shells to cause them .to collectively :serve as the anode.

The method :of' .preparingjsheets of. stripped electrolytically deposited shell 'for use: as a, source of anode metal which comprises: foldingback-the lateral-margins of :eachsheet to provide thickened reinforced .-lat.eral edges thereon, thereafter medially "folding each sheet upon it'self so "that its two lateral halves are in substantiallyface abutting relation, interfoliating said 'folded sheets, and manipulating-said sheets =in-to collective flattened arcuateform.

8. In theart of electroplatingcylinders, where in electric current is passed through an electrolyte from=a soluble'anode across'an intervening space to "the contiguous surface of a ;cathode cylinder to beplated, the method which comprises: physically stripping a platedirshell from a previously plated cylinder, thereafter physically manipulating the stripped shell into flattened arcuate form, abuttingthe thus flattenedstripped shell'against the convex sidedf anzarcuate grid, and thereafter supporting the grid and the shell in substantially coaxial spaced relation-t0 the cylinder to=be plated while'feeding the positive electric current to such 'shelltocause it toiserve as the anode.

"9. In the art of electroplating cylinders; wherein electric current is passed throughfan electrolyte from an anode across-tan intervening space ":to'

the contiguous surf ace of a cathodezcylindertto be plated, the imeth'od -'wllhzhteomprises: physically stripping a platedshell'z from -previously plated cylinder, thereafteriphysically manipulating the stripped shell i'nto flattene'darcuate form, placingsaid stripped shell upon a supporting 'surface contiguous to the cylinder and. substantially coaxial therewith and immersed inthe electrolyte, and maintaining said stripped shell; in a position wherein it-is in substantially coaxial spacedirelation to the cylinder 'zto be "plated Iby :aielectric grid interposed between the strippedshell and the cylinder while feeding positive electric-current to such stripped shellto cause-iit Lto:serve=as the anode.

SILAS LCOULSON.

REFERENCES CITED The following references are of record in the file of this patent:

. UNITED "STATESIPAJTENTS Number Name Date 426,788 Farmer Apr. 29,1890 460,354 Von'Siemens Sept. 29, 1891 519,595 Tho'fehrn "May 8, 1894 "791,341 Harrison et a1 May 30, 1905 908,237 Gamble Dec, 29, 1908 1,029,965 Aylsworth June 18, 1912 1,574,188 Friedman Feb. 23,1926 1,836,368 .Eppensteiner et a1. Dec.-l5, 1931 2,011,638 Jephson Aug. 20,- 1935 2,055,070 :Ericksson "Sept 22, 1936 2155392 Ballard Apr. 25, 1939 2,195,096 Sackner'et'al. 'Mar.'25, 1940 2,335,060 Harris Nov. 23, 1943 FOREIGN, PATENTS Number Country 7 Date 122,433 Great Britain Jan.'30, 1919 324,326 Great-Britain June 20, 1930 740,064 France Nov. "12, 1932 OTHER REFERENCES Transactions of American Electrochemical. So ciety, vol; 30, pages' 144, 1916. 1 1 

